Lcd device

ABSTRACT

A high-speed-drive liquid crystal display device easily applicable to dot inversion driving is provided. Gate lines (GL1 to GL6) each has a shorter drive time in one frame than each one of gate lines (GLm to GL(m+5) and GL(n−5) to GLn).

TECHNICAL FIELD

The present invention relates to a high-speed-drive liquid crystaldisplay device.

BACKGROUND ART

High-speed driving of a liquid crystal display device is in demand. Inparticular, a liquid crystal display device configured to be driven by acolor-field sequential system requires a driving speed several times ashigh as the driving speed of a liquid crystal display device configuredto be driven by a common driving system. The color-field sequentialsystem denotes a driving system for controlling a liquid crystal panelto sequentially display subframes in synchronism with a lighting timingof backlights. The subfranes correspond to the respective three primarycolors. The backlights correspond to the respective three primarycolors.

In the liquid crystal display device, all pixels have to be chargedsufficiently in order to prevent degradation of image quality.

PTL 1 discloses a technique for sufficiently charging all pixels in ahigh-speed-drive liquid crystal display device. In a liquid crystaldriving method according to PTL 1, a horizontal scanning periodcorresponding to the positive polarity in which charging is difficult(sufficient charging requires time) is increased, and a horizontalscanning period corresponding to the negative polarity is reduced. Here,the sum of one horizontal scanning period corresponding to the positivepolarity and one horizontal scanning period corresponding to thenegative polarity equals two horizontal scanning periods in a commondriving system. This enables all pixels to be sufficiently charged whilea decrease in driving speed of the liquid crystal display device issuppressed.

CITATION LIST Patent Literature

PTL 1: Japanese Unexamined Patent Application Publication No.2002-108288 (published on Apr. 10, 2002)

SUMMARY OF INVENTION Technical Problem

In a conventional liquid crystal display device, typically, liquidcrystal display device driven by the liquid crystal driving methodaccording to PTL 1, a source line closer to a source driver has asmaller time constant. Thus, a pixel closer to the source driverrequires a shorter charging time. A reason why the source line closer tothe source driver has a smaller time constant is as follows. That is,the closer the source driver, the shorter the wiring length of thesource line, and thus, the resistance value becomes small, which leadsto a smaller time constant. On the other hand, at a location farthestfrom the source driver, the resistance value is large correspondingly tothe entire length of the source line, which leads to a large timeconstant. Note that a capacity component has substantially the samevalue even when the distance from the source driver varies.

A conventional liquid crystal display device, however, does not take therelationship between the distance of each pixel to the source driver andthe time required to charge each pixel into consideration. Thus,charging pixels closer to the source driver take an unnecessarily longertime. The unnecessarily longer time hinders high-speed driving of theliquid crystal display device.

Moreover, a large-size liquid crystal display device, typically, atelevision set, requires performing so-called dot inversion driving forinverting the polarity by adjacent pixels in order to secure desiredimage quality. PTL 1 proposes a driving method adopting a polarityarrangement similar to the dot inversion driving, but the driving methodcannot fully achieve the dot inversion driving. This is because in thedriving method, a line of negative polarity in a row (a line reducingthe horizontal scanning period) has to be included in the polarityarrangement. Thus, applying the liquid crystal driving method accordingto PTL 1 to the dot inversion driving is difficult.

In view of the above problem, it is an object of the present inventionto provide a high-speed-drive liquid crystal display device easilyapplicable to dot inversion driving.

Solution to Problem

To solve the problem, a liquid crystal display device according to oneaspect of the present invention includes: a plurality of first gatelines; a plurality of first source lines disposed to intersect theplurality of first gate lines; a first pixel formed at least one ofintersections of the plurality of first gate lines and the plurality offirst source lines; a first source driver configured to supply a firstdrive signal to end parts of the plurality of first source lines todrive the plurality of first source lines, wherein the plurality offirst gate lines include a first group including one or a plurality ofthe first gate lines adjacent to each other, the first group includingat least a first proximal gate line which is the first gate line closestto the first source driver, and a second group including one or aplurality of the first gate lines adjacent to each other, the secondgroup being disposed on an opposite side of the first group from thesource driver, and at least all the first gate lines included in thefirst group except for the first proximal gate line each have a shorterdriving time in one frame than each of the first gate lines included inthe second group.

Advantageous Effects of Invention

The one aspect of the present in enables a high-speed-drive liquidcrystal display device easily applicable to dot inversion driving to berealized.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a timing chart illustrating driving of a liquid crystaldisplay device according to a first embodiment of the present invention.

FIG. 2 is a block diagram illustrating main components of the liquidcrystal display device according to the first embodiment of the presentinvention.

FIG. 3 is a timing chart illustrating driving of a liquid crystaldisplay device according to a comparative example.

FIG. 4 is a timing chart illustrating how video data is converted alongwith the driving illustrated in FIG. 1.

FIG. 5 is a block diagram illustrating main components of a liquidcrystal display device according to a second embodiment of the presentinvention.

FIG. 6 is a timing chart illustrating driving of the liquid crystaldisplay device according to the second embodiment of the presentinvention.

FIG. 7 is a timing chart illustrating driving of a liquid crystaldisplay device according to a third embodiment of the present invention.

FIG. 8 is a view illustrating a liquid crystal display device accordingto a fourth embodiment of the present invention and the usage example ofthe liquid crystal display device.

DESCRIPTION OF EMBODIMENTS First Embodiment

FIG. 1 is a timing chart illustrating driving of a liquid crystaldisplay device 100 according to a first embodiment of the presentinvention. FIG. 2 is a block diagram illustrating main components of theliquid crystal display device 100 according to the first embodiment ofthe present invention.

As illustrated in FIG. 2, the liquid crystal display device 100 includesn (a plurality of) gate lines (first gate lines) GL, p (a plurality of)source lines (first source line) SL, a plurality of transistors T andpixels (first pixels) P, a gate driver 1, and a source driver (firstsource driver) 2.

In the liquid crystal display device 100, the gate lines GL are arrangedto intersect the source lines SL. The gate lines GL are arranged from aside where the source driver 2 is provided, that is, from top to bottomin the order of a gate line (first proximal gate line) GL1, a gate lineGL2, . . . , a gate line GL(n−1), and a gate line GLn. The source linesSL are arranged in the order of a source line SL1, a source line SL2, .. . , and a source line SLp from the gate driver 1.

The transistor T and the pixel P are formed at least one ofintersections of the n gate lines GL and the p source lines SL. For oneintersection of the gate line GL and the source line SL the gate of thetransistor S is connected to the gate line GL, the source of thetransistor T is connected to the source line SL, and the pixel P isconnected to the drain of the transistor T.

Here, the p source lines SL are arranged from the source line SL1 to thesource line SLp in the order of a source line SL_OE, a source lineSL_EO, a source line SL_EO, and a source line SL_OE for each four sourcelines SL. Different signals may be supplied to the p source lines SL,but one of any two adjacent pixels of the plurality of pixels P isdriven by the source line SL_OE, and the other of the two adjacentpixels is driven by the source line SL_EO. A connection relationshipbetween each source line SL and each transistor T and pixel P isdetermined so as to be able to realize such driving.

Note that in FIG. 2, pixel groups P1 to Pn are defined. The pixel groupsP1 to Pn are collections of the pixels P connected to the gate lines GL1to GLn respectively via the corresponding transistors T.

The gate driver 1 is disposed on a side of the source line SL1 and isconfigured to supply a gate drive signal to the n gate lines GL to drivethe n gate lines GL. The source driver 2 is disposed on an upper side ofthe gate line GL1 and is configured to supply a source drive signal(first drive signal) to the p source lines SL to drive the p sourcelines SL.

Here, the liquid crystal display device 100 is driven by dot inversiondriving and so-called double-source driving. In the liquid crystaldisplay device 100, the dot inversion driving enables desired imagequality to be secured even in a case of a large-size liquid crystaldisplay device, typically, a television set. That is, the gate driver 1and the source driver 2 operate as described below.

That is, the gate driver 1 is configured to supply an identical gatedrive signal to the gate lines GL1 and the gate lines GL2. Specifically,the gate driver 1 is connected to a common gate line GL12 to which thegate drive signal for driving the gate line GL1 and the gate line GL2 issupplied. The common gate line GL12 is separated into the gate line GL1and the gate line GL2. In other words, the pixels P belonging to thepixel group P1 and the pixels P belonging to the pixel group P2 arebrought into an on state at the same timing. The gate driver 1 and eachgate line GL are configured such that similarly to the combination ofthe gate line GL1 and the gate line GL2, an identical gate drive signalis supplied to each of a combination of the gate line GL3 and the gateline GL4, . . . , and a combination of the gate line GL(n−1) and thegate line GLn.

Moreover, the source driver 2 is configured to supply an identicalsource drive signal to the source lines SL_OE and to supply an identicalsource drive signal to the source lines SL_EO. In one frame, the sourcelines SL_OE are driven such that the source drive signal of the sourcelines SL_OE corresponds to the positive polarity, and the source linesSL_EC are driven such that the source drive signal of the source linesSL_EO corresponds to the negative polarity. In next one frame, thesource lines SL_OE are driven such that the source drive signal of thesource lines SL_OE corresponds to the negative polarity, and the sourcelines SL_EO are driven such that the source drive signal of the sourcelines SL_EO corresponds to the positive polarity. As a result, any twoadjacent pixels of the plurality of pixels P are in a relationship ofinversion polarity (i.e., one of the two pixels has the positivepolarity and the other of the two pixels has the negative polarity).Thus, in the liquid crystal display device 100, the dot inversiondriving is realized.

In the liquid crystal display device 100, the source lines SL closer tothe source driver 2 have smaller time constants, and thus the pixels Pcloser to the source driver 2 require shorter charging times. That is,in the liquid crystal display device 100, a time required to charge thepixels P belonging to the pixel group P1 is shortest, and the timerequired to charge the pixels P increases in the order of the pixels Pbelonging to the pixel group P2, . . . , the pixels P belonging to thepixel group Pn. Thus, in order to realize high-speed driving of theliquid crystal display device 100, the liquid crystal display device 100is driven as described below according to the timing chart shown in FIG.1.

In FIG. 1, the period t1 is a period corresponding to one frame of theliquid crystal display device 100.

A gate drive signal GSA is a gate drive signal for driving the gate lineGL1 and the gate line GL2 (in other words, supplied to the common gateline GL12). A gate drive signal GSB is a gate drive signal for drivingthe gate line GL3 and the gate line GL4. A gate drive signal GSC is agate drive signal for driving the gate line GL5 and the gate line GL6.The gate drive signal GSA, the gate drive signal GSB, and the gate drivesignal GSC are pulse signals. Moreover, the pulse width of the gatedrive signal GSA, the pulse width of the gate drive signal GSB, and thepulse width of the gate drive signal GSC are equal to one another andare each a pulse width GSa. The gate lines GL1 to GL6 correspond to afirst group. Moreover, the gate lines GL1 and GL2 correspond to a firstsubgroup, and the gate lines GL3 to GL6 corresponds to a secondsubgroup. Moreover, the gate line GL1 is a gate line of the gate linesGL which is closest to the source driver 2, and thus, as describedabove, the gate line GL1 corresponds to the first proximal gate line.

A gate drive signal GSQ is a gate drive signal for driving the gate lineGLm and the gate line GL(m+1). A gate drive signal GSR is a gate drivesignal for driving the gate line GL(m+2) and the gate line GL(m+3). Agate drive signal GSS is a gate drive signal for driving the gate lineGL(m+4) and the gate line GL(m+5). Note that m is an integer larger thanor equal to seven, and m+5 is smaller than or equal to n−6. The gatedrive signal GSQ, the gate drive signal GSR, and the gate drive signalGSS are pulse signals. Moreover, the pulse width of the gate drivesignal GSQ, the pulse width of the gate drive signal GSR, and the pulsewidth of the gate drive signal GSS are equal to one another and are eacha pulse width GSq. The gate lines GLm to CL(m+5) correspond to one ofthe second groups.

A gate drive signal GSX is a gate drive signal for driving the gate lineGL(n−5) and the gate line GL(n−4). A gate drive signal GSY is a gatedrive signal for driving the gate line GL(n−3) and the gate lineGL(n−2). A gate drive signal GSZ is a gate drive signal for driving thegate line GL(n−1) and the gate line GLn. The gate drive signal GSX, thegate drive signal GSY, and the gate drive signal GSZ are pulse signals.Moreover, the pulse width of the gate drive signal GSX, the pulse widthof the gate drive signal GSY, and the pulse width of the gate drivesignal GSZ are equal to one another and are each a pulse width GSx. Thegate lines GL(n−5) to GLn correspond to another one of the secondgroups.

The pulse width GSa, the pulse width GSq, and the pulse width GSx are inthe following relationship: pulse width GSa <pulse width GSq<pulse widthGSx. In other words, the drive time of each of the gate lines GL1 to GL6defined by the pulse width GSa is shorter than the drive time of each ofthe gate lines GLm to GL(m+5) defined by the pulse width GSq. Moreover,the drive time of each of the gate lines GL1 to GL6 and the drive timeof each of the gate lines GLm to GL(m+5) are each shorter than the drivetime of each of the gate line GL(n−5) to GLn defined by the pulse widthGSx.

Note that in the present embodiment, each of the first group and twosecond groups includes six gate lines GL adjacent to each other. Notethat the number of the gate lines GL included in the first group and thenumber of gate lines GL included in each second group are each at leastone.

Moreover, in FIG. 1, the source drive signal in each source line SL_OEand the source drive signal in each source line SL_EO which the sourcedriver 2 outputs are shown together. In FIG. 1, a potential COM denotesa potential of a counter electrode (not shown) included in the liquidcrystal display device 100. Moreover, in FIG. 1, a signal SS_OE denotesthe source drive signal in each source line SL_OE which the sourcedriver 2 outputs, and a signal SS_EO denotes the source drive signal ineach source line SL_EO which the source driver 2 outputs. Moreover, inFIG. 1, a potential VP_OE denotes the potential of a pixel electrode(not shown) of one of pixels P driven by the signal SS_OE, and apotential VP_EO denotes the potential of a pixel electrode of one ofpixels P driven by the signal SS_EO. The signal SS_OE rises at a risingtiming of the gate drive GSA, and then, the signal SS_OE repeatedlyfalls and rises in synchronism with a rise of each of the gate drivesignals GSB to GSZ. On the other hand, the signal SS_EO falls at therising timing of the gate drive signal GSA, and then, the signal SS_EOrepeatedly rises and falls in synchronism with a rise of each of thegate drive signals GSB to GSZ. Each of the signal SS_OE and the signalSS_EO charges a corresponding one of the pixels P with the positivepolarity during a period from the start of a rise to the start of a nextfall and charges the corresponding one of the pixels P with the negativepolarity during a period from the start of a fall to the start of a nextrise.

In this embodiment, a period of one pulse of the signal SS_OE and thesignal SS_EO corresponding to the gate drive signal GSA is defined as aperiod SSa. Moreover, a period of one pulse of the signal SS_OE and thesignal SS_EO corresponding to the gate drive signal GSQ is defined as aperiod SSq. Furthermore, a period of one pulse of the signal SS_OE andthe signal SS_EO corresponding to the gate drive signal GSX is definedas a period SSx. As described above, since pulse width GSa<pulse widthGSq<pulse width GSx, the following relationship holds true: periodSSa<period SSg>period SSx. In other words, this means that the pixels Pcloser to the source driver 2 have shorter charging times. Note that theperiod SSa (pulse width GSa) corresponds to a length of a period duringwhich all the pixels P belonging to the pixel group P6 can besufficiently charged by the signal SS_OE and the signal SS_EO. Moreover,the period SSq (pulse width GSq) corresponds to a length of a periodduring which all the pixels P belonging to the pixel group P(m+5) can besufficiently charged by the signal SS_OE and the signal SS_EO.Furthermore, the period SSx (pulse width GSx) corresponds to a length ofa period during which all the pixels P belonging to the pixel group Pncan be sufficiently charged by the signal SS_OE and the signal SS_EO.

In the liquid crystal display device 100, the distance of each pixel Pto the source driver 2 and a time required to charge each pixel P aretaken into consideration, and as the distance to the source driver 2decreases, the charging time of each pixel P is reduced. Thus, it ispossible to reduce an excessive time for charging pixels P close to thesource driver 2 (in this embodiment, pixels P belonging to the pixelgroup P1 and pixels belonging to the pixel group P2). This enables theliquid crystal display device 100 to be driven at a further increasedspeed.

In this embodiment, in order to describe the effect of the liquidcrystal display device 100 in more detail, the driving of the liquidcrystal display device 100 shown in FIG. 1 is compared with driving of aliquid crystal display device according to a comparative example shownin FIG. 3. FIG. 3 is a timing chart illustrating the driving of theliquid crystal display device according to the comparative example.

As illustrated in FIG. 3, in the driving of the liquid crystal displaydevice according to the comparative example, gate drive signals GSA toGSZ have all the same pulse width. In this case, to sufficiently chargeall pixels P, in particular, all pixels P belonging to a pixel group Pn,the pulse width (drive time) of each of the gate drive signals GSA toGSZ has to be the pulse width GSx shown in FIG. 1.

In the driving of the liquid crystal display device according to thecomparative example, the period of one pulse of signal SS_OE and asignal SS_EO during charging of all pixels P belonging to pixel groupsP1 to P6 is a period SSx. However, charging of all pixels P belonging tothe pixel groups P1 to P6 is actually completed in the period SSa (seeFIG. 1) shorter than the period SSx. Thus, a period obtained bysubtracting The period SSa from the period SSx (in FIG. 3, the periodSS(x-a)) is a wasted period during the charging of all pixels Pbelonging to the pixel groups P1 to P6. Similarly, in the driving of theliquid crystal display device according to the comparative example,charging of all pixels P belonging to pixel groups Pm to P(m+5) isactually completed in the period SSq (see FIG. 1) shorter than theperiod SSx. Thus, a period (in FIG. 3, a period. SS(x-q)) obtained bysubtracting the period SSx from the period SSq is a wasted period duringthe charging of all pixels P belonging to the pixel groups Pm to P(m+5).

Thus, the period t2 in FIG. 3 corresponding to one frame of the liquidcrystal display device according to the comparative example also becomeslonger than the above-described period t1 shown in FIG. 1.

FIG. 4 is a timing chart illustrating how video data is converted alongwith the driving illustrated in FIG. 1.

Although not show in FIG. 2, the liquid crystal display device 100includes a video processing circuit (e.g., a known timing controller)including frame memory. During the driving of the liquid crystal displaydevice 100, the frame memory accumulates data of one frame (how the datais accumulated is not shown). The data which is accumulated issynchronized with a clock which can be driven with a minimum gate linewidth (FIG. 1, the period SSa), and the data is supplied to the sourcedevice 2. The period SSa is determined in accordance with a longer oneof a time of scanning (CLK frequency) of one horizontal intervalcorresponding to the driving speed of the source driver 2 and a minimumtime in which at least one pixel P can be charged.

As illustrated in FIG. 4, the timing controller transfers an operationclock CLK, a data enable signal DE, and an image data signal DATA (notshown) which are input to the timing controller to, for example, ahigher-speed operation clock in the timing controller to generate aconverted operation clock CLK′, a converted data enable signal DE′, anda converted image data signal DATA′ (not shown). The converted operationclock CLK′, the converted data enable signal DE′, and the convertedimage data signal DATA′ are driven constantly, and the pulse widths ofthese signals are adjusted by the blanking interval of one horizontalinterval and the timing of a latch signal LS. Thus, even when the sourcedriver 2 is a known source driver, the driving shown in FIG. 1 becomespossible. This method also enables driving with a pulse width largerthan one horizontal interval of the input signal, and thus, the drivingis possible even in a case of a liquid crystal panel in which thedriving was previously not possible. The latch signal LS and the gateclock GCK are generated by a signal LGT (LS, GCK timing). The signal LGTis a signal read from a look-up table (LUT) or the like in which signalsconfigured in accordance with the time constant at each control locationof the liquid crystal display device 100 are stored. Thus, even when thegate driver 1 is a known gate driver, the driving shown in FIG. 1becomes possible.

According to the driving of the liquid crystal display device 100described above, toe pulse widths of the gate drive signals GSA to GSZare reduced on a side adjacent to the source driver 2 and are increasedon a side away from the source driver 2 in accordance with the timeconstants of the source lines SL. Thus, a period corresponding to oneframe can be reduced from the period t2 shown in FIG. 3 to the period t1shown in FIG. 1.

Second Embodiment

FIG. 5 is a block diagram illustrating main components of a liquidcrystal display device 200 according to a second embodiment of thepresent invention. FIG. 6 is a timing chart illustrating driving of theliquid crystal display device 200 according to the second embodiment ofthe present invention.

An liquid crystal display device 200 illustrated in FIG. 5 includes, inaddition to the components of the liquid crystal display device 100, n(a plurality of) gate lines (second gate lines) GL-2, p (a plurality of)source lines (second source line) SL-2, a plurality of transistors T-2and pixels (second pixels) P-2, a gate driver 1-2, and a source driver(second source driver) 2-2.

In the liquid crystal display device 200, the gate lines GL-2 arearranged to intersect the source lines SL-2. The gate lines GL-2 arearranged from a side where the source driver 2-2 is provided, that is,from bottom to top in the order of a gate line (second proximal gateline) GL1-2, a gate line GL2-2, . . . , a gate line GL(n−1)-2, and agate line GLn−2. The source lines SL-2 are arranged in the order of asource line SL1-2, a source line SL2-2, . . . , and a source line SLp-2from the gate driver 1-2. The gate line GLn and the gate line GLn−2 areadjacent to each other in the up-down direction.

The transistor T-2 and the pixel P-2 are formed at least one ofintersections of the n gate lines GL-2 and the p source lines SL-2. Forone intersection of the gate line GL-2 and the source line SL-2, thegate of the transistor T-2 is connected to the gate line GL-2, thesource of the transistor T-2 is connected to the source line SL-2, andthe pixel P-2 is connected to the drain of the transistor T-2.

Here, the p source lines SL-2 are arranged from the source line SL1-2 tothe source line SLp-2 in the order of a source line SL_OE-2, a sourceline SL_EO-2, a source line SL_EO-2, and a source line SL_OE-2 for eachfour source lines SL-2. Different signals may be supplied to the psource lines SL-2, but one of any two adjacent pixels of the pluralityof pixels P-2 is driven by the source line SL_OE-2, and the other of thetwo adjacent pixels is driven by the source line SL_EO-2. A connectionrelationship between each source line SL-2 and each transistor T-2 andpixel P-2 is determined so as to be able to realize such driving.

Note that in FIG. 5, pixel groups P1-2 to Pn-2 are defined. The pixelgroups P1-2 to Pn-2 are collections of pixels P-2 connected to the gatelines GL1-2 to GLn-2 respectively via the corresponding transistors T-2.

The gate driver 1-2 is disposed on a side of the source line SL1-2 andis configured to supply a gate drive signal to the n gate lines GL-2 todrive the n gate lines GL-2. The source driver 2-2 is disposed on alower side of the gate line GL1-2 and is configured to supply a sourcedrive signal (second drive signal) to the p source lines SL-2 to drivethe p source lines SL-2. The source drive signal supplied to the psource lines SL from the source driver 2 and the source drive signalsupplied to the p source lines SL-2 from the source driver 2-2 will bedescribed later.

Here, the liquid crystal display device 200 is, similarly to the liquidcrystal display device 100, driven by dot inversion driving anddouble-source driving. That is, the gate driver 1 and the source driver2 operate in a similar manner to those of the liquid crystal displaydevice 100, and the gate driver 1-2 and the source driver 2-2 operate asdescribed below.

That is, the gate driver 1-2 is configured to supply an identical gatedrive signal to the gate lines GL1-2 and the gate lines GL2-2. Theprinciple of the supply is the same as the principle that the gatedriver 1 supplies an identical gate drive signal to the gate line GL1and the gate line GL2, and thus, the detailed description will beomitted in this embodiment. The gate driver 1-2 and each gate line GL-2are configured such that similarly to the combination of the gate lineGL1-2 and the gate line GL2-2, an identical gate drive signal issupplied to each of a combination of the gate line GL3-2 and the gateline GL4-2, . . . , and a combination of the gate line GL(n−1)-2 and thegate line GLn-2.

Moreover, the source driver 2-2 is configured to supply an identicalsource drive signal to the source lines SL_OE-2 and to supply anidentical source drive signal to the source lines SL_EO-2 based on aprinciple similar to the principle of the source driver 2. Note that inthe liquid crystal display device 200, any adjacent pixel P and pixelP-2 respectively belonging to the pixel group Pn and the pixel groupPn-2 are in a relationship of inverted polarity. Thus, in the liquidcrystal display device 200, the dot inversion driving is realized.

In the liquid crystal display device 200, the source lines SL-2 closerto the source driver 2-2 have smaller time constants, and thus, thepixels P-2 closer to the source driver 2-2 require shorter chargingtimes. That is, in the liquid crystal display device 200, a timerequired to charge the pixels P-2 belonging to the pixel group P1-2 isshortest, and the time required to charge the pixels P-2 increases inthe order of the pixels P-2 belonging to the pixel group P2-2, . . . ,the pixels P-2 belonging to the pixel group Pn-2. Thus, in order torealize high-speed driving of the liquid crystal display device 200, theliquid crystal display device 200 is driven as described below accordingto the timing chart shown in FIG. 6.

It can be said that FIG. 6 is a figure in which the contents describedbelow are added to the timing chart shown in FIG. 1.

A gate drive signal GSA-2 is a gate drive signal for driving the gateline GL1-2 and the gate line GL2-2. A gate drive signal GSB-2 is a gatedrive signal for driving the gate line GL3-2 and the gate line GL4-2. Agate drive signal GSC-2 is a gate drive signal for driving the gate lineGL5-2 and the gate line GL6-2. The gate drive signal GSA-2, the satedrive signal GSB-2, and the gate drive signal GSC-2 have the same risingtiming, falling timing, and pulse width (pulse width GSa) as the gatedrive signal GSA, the gate drive signal GSB, and the gate drive signalGSC respectively. The gate lines GL1-2 to GL6-2 correspond to a thirdgroup. Moreover, the gate line GL1-2 is a gate line of the gate linesGL-2 which is closest to the source driver 2-2, and thus, as describedabove, the gate line GL1-2 corresponds to the second proximal gate line.

A gate drive signal GSQ-2 is a gate drive signal for driving the gateline GLm-2 and the gate line GL(m+1)-2. A gate drive signal CSR-2 is agate drive signal for driving the gate line GL(m+2)-2 and the gate lineGL(m+3)-2. A gate drive signal CSS-2 is a gate drive signal for drivingthe gate line CL (m+4)-2 and the gate line GL(m+5)-2. The gate drivesignal GSQ-2, the gate drive signal GSR-2, and the gate drive signalGSS-2 have the same rising timing, falling timing, and pulse width(pulse width GSq) as the gate drive signal GSQ, the gate drive signalGSR, and the gate drive signal GSS respectively. The gate lines GLm-2 toGL(m+5)-2 correspond to one of fourth groups.

A gate drive signal GSX-2 is a gate drive signal for driving the gateline GL(n−5)-2 and the gate line GL(n−4)-2. A gate drive signal GSY-2 isa gate drive signal for driving the gate line GL(n−3)-2 and the gateline GL(n−2)-2. A gate drive signal CSZ-2 is a gate drive signal fordriving the gate line GL(n−1)-2 and the gate line GLn-2. The gate drivesignal GSX-2, the gate drive signal GSY-2, and the gate drive signalCSG-2 have the same rising timing, falling timing, and pulse width(pulse width GSX) as the gate drive signal GSX, the gate drive signalGSY, and the gate drive signal CSZ respectively. The gate linesGL(n−5)-2 to GLn-2 correspond to another one of the fourth groups.

Note that in the present embodiment, each of the third group and the twofourth groups includes six gate lines GL-2 adjacent to each other. Notethat the number of the gate lines GL-2 included in the third group andthe number of gate lines GL-2 included in each fourth group are each atleast one.

Moreover, in FIG. 6, a signal SS_OE-2 and a signal SS_EO-2 which thesource driver 2-2 outputs are shown together. The signal SS_OE-2 is asource drive signal in each source line SL_OE-2. The signal SS_EO-2 is asource drive signal in each source line SL_EO-2. As shown in FIG. 6, thewaveform of the signal SS_OE-2 and the waveform of the signal SS_EO-2are respectively the same as the waveform of the signal SS_OE and thewaveform of the signal SS_EO.

In the liquid crystal display device 200, the distance of each pixel P-2to the source driver 2-2 and a time required to charge each pixel P-2are taken into consideration, and as the distance to the source driver2-2 decreases, the charging time of each pixel P-2 is reduced. Thus, itis possible to reduce an excessive time for charging pixels P-2 close tothe source driver 2-2 (in this embodiment, pixels P-2 belonging to thepixel group P1-2 and the pixel group P2-2). This enables the liquidcrystal display device 200 to be driven at a further increased speed.

Moreover, as can be clearly seen from FIG. 6, in the liquid crystaldisplay device 200, it is possible to make waveforms of signals outputfrom the gate driver 1 and the source driver 2 and waveforms of signalsoutput from the gate driver 1-2 and the source driver 2-2 identical toeach other. This enables these drivers to be driven collectively.

That is, if it is possible to drive a set of the gate driver 1 and thesource driver 2 and a set of the gate driver 1-2 and the source driver2-2 independently of each other, the waveforms of the signals outputfrom the gate driver 1 and the source driver 2 may be different from thewaveforms of signals output from the gate driver 1-2 and the sourcedriver 2-2. However, this may complicate the structure of the liquidcrystal display device 200. Making the waveforms of the signals outputfrom the gate driver 1 and the source driver 2 and the waveforms of thesignals output from the gate driver 1-2 and the source driver 2-2identical to each other enables prevention of complication of thestructure of the liquid crystal display device 200.

The liquid crystal display device 200 enables a further increase in sizeand/or definition as compared to the liquid crystal display device 100.

Note that in the description above, the gate lines GL, are drivensequentially in the order from the gate line GL1 close to the sourcedrive 2, and the gate lines GL-2 are driven sequentially the order fromthe gate line GL1-2 close to the source drive 2-2, but the driving orderof the gate lines is not limited to the description above. That is, thegate lines GL, may be driven sequentially in the order from the gateline GLn far from the source drive 2, and the gate lines GL-2 may bedriven sequentially in the order from the gate line GLn-2 far from thesource drive 2-2.

Moreover, an example in which the waveforms of the signals output fromthe gate driver 1 and the source driver 2 are different from thewaveforms of the signals output from the gate driver 1-2 and the sourcedriver 2-2 is as follows. That, the gate lines GL are drivensequentially in the order from the gate line GL1 close to the sourcedrive 2, and the gate lines GL-2 are craven sequentially in the orderfrom the gate line GLn-2 far from the source drive 2-2. Based on such anexample, the liquid crystal display device 200 may be driven.

Moreover, in the liquid crystal display device 200, the number of gatelines GL and the number of gate lines GL-2 are the same (n). Note thatthe number of gate lines GL and the number of gate lines GL-2 may bedifferent from each other.

Third Embodiment

FIG. 7 is a timing chart illustrating driving of a liquid crystaldisplay device 300 according to a third embodiment of the presentinvention. The configuration of the liquid crystal display device 300 isthe same as the configuration of the liquid crystal display device 100(see FIG. 2). The driving of the liquid crystal display device 300 isdifferent from the driving of the liquid crystal display device 100 inthe following points.

During the driving of the liquid crystal display device 300, a gatedrive signal GSA has a pulse width GSw. The pulse width GSw is largerthan the pulse width GSa. Note that, a period of one pulse of a signalSS_OE and a signal SS_EO corresponding to a gate drive signal GSA ofFIG. 7 is a period SSw. On the other hand, the pulse width of each ofgate drive signals GSB to GSZ in the liquid crystal display device 300is the same as the pulse width of each of the gate drive signals GSB toGSZ in the liquid crystal display device 100. That is, all gate linesGL1 and GL2 included in a first subgroup each have a longer drive timein one frame than each one of gate lines GL3 to GL6 included in a secondsubgroup.

This enables the liquid crystal display device 300 drivable at a highspeed to be realized while the charging time of each of the pixel groupsP1 to Pn is optimized. That is, immediately after the start of a nextframe following one frame, the polarity of the source drive signal isinverted (for a subsequent one frame, the polarity is not inverted).Thus, each source line SL has to be charged to an inverted polarity onlyat a polarity inversion timing of the source device signal, and thus thecharging time has to be slightly increased. The liquid crystal displaydevice 300 can sufficiently secure a time for charging each source lineto the inverted polarity. Note that even when the configuration of theliquid crystal display device 300 is the same as the configuration ofthe liquid crystal display device 200, driving similar to that describedabove can be performed.

Fourth Embodiment

FIG. 8 is a view illustrating a liquid crystal display device 400according to a fourth embodiment of the present invention and a usageexample of the liquid crystal display device 400. FIG. 8 shows theappearance of the liquid crystal display device 400. The liquid crystaldisplay device 400 is one of the liquid crystal display device 100, theliquid crystal display device 200, and the liquid crystal display device300. The liquid crystal display device 400 includes a display unit 401for displaying an image, video, and the like. The display unit 401 istransparent.

As shown in FIG. 8, the liquid crystal display device 400 whose displayunit 401 is transparent has a square shape in front view, but three offour sides of the square have no frame portion. Thus, the liquid crystaldisplay device 400 enables an enlarged scope of application and designinnovations to be realized with respect to conventional liquid crystaldisplay devicees.

For example, in FIG. 8, a woman behind the liquid crystal display device400 can show an object to a man in front of the liquid crystal displaydevice 400 through the display unit 401. Moreover, even when the liquidcrystal display device 400 is placed on a counter or the like, nostrange feeling is caused, and thus, it can be said that the design ofthe liquid crystal display device 400 is excellent.

A technique for realizing transparency of the display unit 401 is atechnique of omitting a color filter of the liquid crystal displaydevice 400 to increase the transparency of the display unit 401. Inorder to realize such a technique, the liquid crystal display device 400has to be driven by the color-field sequential system, that is, the RGBbacklight (not shown) has to be switched by frame units, and thus,high-speed driving is required.

The liquid crystal display device 400 is one of the liquid crystaldisplay device 100, the liquid crystal display device 200, and theliquid crystal display device 300, and thus, the high-speed driving isrealized.

SUMMARY

A liquid crystal display device according to a first aspect of thepresent invention includes a plurality of first gate lines (gate linesGL), a plurality of first source lines (source lines SL) disposed tointersect the plurality of first gate lines; a first pixel (pixel P)formed at least one of intersections of the plurality of first gatelines and the plurality of first source lines; a first source driver(source driver 2) configured to supply a first drive signal to end partsof the plurality of first source lines to drive the plurality of firstsource lines, wherein the plurality of first gate lines include a firstgroup (gate lines GL1 to GL6) including one or a plurality of the firstgate lines adjacent to each other, the first group including at least afirst proximal gate line (gate line GL1) which is the first gate lineclosest to the first source driver, and a second group (gate lines GLmto GL(m+5) and gate lines GL(n−5) to GLn) including one or a pluralityof the first gate lines adjacent to each other, the second group beingdisposed on an opposite side of the first group from the source driver,and at least all the first gate lines included in the first group exceptfor the first proximal gate line each have a shorter driving time in oneframe than each of the first gate lines included in the second group.

With the above-described configuration, the distance of each pixel tothe first source driver and a time required to charge each pixel aretaken into consideration, and as the distance to the first source driverdecreases, a charging time of each pixel is reduced. Thus, it ispossible to reduce excessive time for charging of pixels close to thefirst source driver. Thus, the above-described configuration enablesdriving at a further increased speed.

In particular, in a liquid crystal display device according to a secondaspect referring to the first aspect, all the first gate lines includedin the first group preferably each have a shorter driving time in oneframe than each of the first gate lines included in the second group.

Moreover, in a liquid crystal display device according to a third aspectreferring to the first aspect, the first group includes a first subgroup(gate line GL1 and gate line GL2) including one or a plurality of thefirst gate lines adjacent to each other, the first subgroup including atleast the first proximal gate line, a second subgroup (gate lines GL3 toGL6) including one or a plurality of the first gate lines adjacent toeach other, the second subgroup being disposed on an opposite side ofthe first subgroup from the source driver, and all the first gate linesincluded in the first subgroup have a longer driving time in one framethan all the first gate lines included in the second subgroup.

This configuration enables a liquid crystal display device drivable at ahigh speed to be realized while the charging time is optimized. That is,for example, when immediately after the start of a next frame followingone frame, the polarity of the first drive signal is inverted (for asubsequent one frame, the polarity is not inverted), each first sourceline has to be charged to an inverted polarity only at a polarityinversion timing of the first device signal, and thus the charging timehas to be slightly increased. With this configuration, it is possible tosufficiently secure a time for charging the first source lines to theinverted polarity.

Moreover, an liquid crystal display device according to a fourth aspectof the present invention referring to any one of the first to thirdaspects further includes a plurality of second gate lines (gate linesGL-2); a plurality of second source lines (source lines SL-2) disposedto intersect the plurality of second gate lines; a second pixel (pixelP-2) formed at least one of intersections of the plurality or secondgate lines and the plurality of second source lines; a second sourcedriver (source driver 2-2) configured to supply a second drive signal toend parts of the plurality of second source lines to drive the pluralityof second source lines, wherein the plurality of second gate linesinclude a third group (gate lines GL1-2 to GL6-2) including one or aplurality of the second gate lines adjacent to each other, the thirdgroup including at least a second proximal gate line (gate line GL1-2)which is the second gate line closest to the second source driver, and afourth group (gate lines GLm−2 to GL(m+5)-2 and gate lines GL(n−5)-2 toGLn−2) including one or a plurality of the second gate lines adjacent toeach other, the fourth group being disposed on an opposite side of thethird group from the second source driver, all the second gate linesincluded in at least the third group except for the second proximal gateline each have a shorter driven g time in one frame than each of thesecond gate lines included in the fourth group, the third group isdriven while the first group is driven, and the fourth group is drivenwhile the second group is driven.

This configuration enables the waveform of a signal output from thefirst source driver and the waveform of a signal output from the secondsource driver to be made identical to each other. This enables thesedrivers to be driven collectively.

Moreover, a liquid crystal display device according to a fifth aspect ofthe present invention referring to, for example, any one of the first tofourth aspects further includes a display which is transparent.

The present invention is not limited to the embodiments described above.Various modifications may be made within the scope of the claims.Embodiments obtained by accordingly combining the techniques disclosedin different embodiments are also within the technical scope of thepresent invention. Moreover, combining technical means disclosed in theembodiments can provide new technical feature.

REFERENCE SIGNS LIST

1 GATE DRIVER

1-2 GATE DRIVER

2 SOURCE DRIVER (FIRST SOURCE DRIVER)

2-2 SOURCE DRIVER (SECOND SOURCE DRIVER)

100 LIQUID CRYSTAL DISPLAY DEVICE

200 LIQUID CRYSTAL DISPLAY DEVICE

300 LIQUID CRYSTAL DISPLAY DEVICE

400 LIQUID CRYSTAL DISPLAY DEVICE

401 DISPLAY UNIT

GL GATE LINE (FIRST GATE LINE)

GL1 GATE LINE (FIRST PROXIMAL GATE LINE)

GL-2 GATE LINE (SECOND GATE LINE)

GL1-2 GATE LINE (SECOND PROXIMAL GATE LINE)

P PIXEL (FIRST PIXEL)

P-2 PIXEL (SECOND PIXEL)

SL SOURCE LINE (FIRST SOURCE LINE)

SL-2 SOURCE LINE (SECOND SOURCE LINE)

1. A liquid crystal display device comprising: a plurality of first gatelines; a plurality of first source lines disposed to intersect theplurality of first gate lines; a first pixel formed at least one ofintersections of the plurality of first gate lines and the plurality offirst source lines; and a first source driver configured to supply afirst drive signal to end parts of the plurality of first source linesto drive the plurality of first source lines, wherein the plurality offirst gate lines include a first group including one or a plurality ofthe first gate lines adjacent to each other, the first group includingat least a first proximal gate line which is the first gate line closestto the first source driver and a second group including one or aplurality of the first gate lines adjacent to each other, the secondgroup being disposed on an opposite side of the first group from thesource driver, and at least all the first gate lines included in thefirst group except for the first proximal gate line each have a shorterdriving time in one frame than each of the first gate lines included inthe second group.
 2. The liquid crystal display device according toclaim 1, wherein all the first gate lines included in the first groupeach have a shorter driving time in one frame than each of the firstgate lines included in the second group.
 3. The liquid crystal displaydevice according to claim 1, wherein the first group includes a firstsubgroup including one or a plurality of the first gate lines adjacentto each other, the first subgroup including at least the first proximalgate line, and a second subgroup including one or a plurality of thefirst gate lines adjacent o each other, the second subgroup beingdisposed on an opposite side of the first subgroup from the sourcedriver, and all the first gate lines included in the first subgroup havea longer driving time in one frame than all the first gate linesincluded in the second subgroup.
 4. The liquid crystal display deviceaccording to claim 1, further comprising: a plurality of second gatelines; a plurality of second source lines disposed to intersect theplurality of second gate lines; a second pixel formed at least one ofintersections of the plurality of second gate lines and the plurality ofsecond source lines; and a second source driver configured to supply asecond drive signal to end parts of the plurality of second source linesto drive the plurality of second source lines, wherein the plurality ofsecond gate lines include a third group including one or a plurality ofthe second gate lines adjacent to each other, the third group includingat least a second proximal gate line which is the second gate lineclosest to the second source driver and a fourth group including One ora plurality of the second gate lines adjacent to each other, the fourthgroup being disposed on an opposite side of the third group from thesecond source driver, all the second gate lines included in at least thethird group except for the second proximal gate line each have a shorterdriving time in one frame than each of the second gate lines included inthe fourth group, the third group is driven while the first group isdriven, and the fourth group is driven while the second group is driven.5. The liquid crystal display device according to claim 1, comprising adisplay which is transparent.